Chip collecting apparatus for tip dresser

ABSTRACT

A chip collecting apparatus for a tip dresser of the present invention has a sideways-mounted dresser main body and a chip pickup case mounted at the end of the dresser main body. Chips generated during dressing electrode tips are picked up in the case and discharged from the chip discharge port opened under the case into a chip collection vessel. A pair of opposite electrode tips held at the ends of a welding gun advances horizontally from the front. Since chip inserting surfaces of the chip pickup case, in which chip insertion ports for receiving the electrode tips are opened, are formed in a wedge shape extending from the front end to the rear end with respect to the advancing direction of the welding gun, the electrode tips can be smoothly guided to the chip insertion ports without unnecessarily increasing the space between the electrode tips.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a chip collecting apparatus for a tip dresser for collecting chips generated when dressing electrode tips.

[0003] 2. Description of the Related Art

[0004] Conventionally, electrode tips used for spot welding or the like are worn out (or deformed) when welding work is repeated. When welding work is performed with a worn-out electrode tip, welding of desired quality cannot be obtained; accordingly, electrode tips are periodically dressed to maintain welding quality.

[0005] For example, Japanese Unexamined Patent Application Publication No. 6-122082 discloses a tip dresser for dressing electrode tips in which after the upper and lower surfaces of a dressing body have been tightly pressed by a pair of electrode tips provided at opposed ends of a welding gun, and the welding gun is swung around the central axis of each electrode tip for grinding, thereby dressing the electrode tips.

[0006] Recently, the recycle of chips is contemplated in view of cost reduction and environmental issues. Accordingly, a collection vessel is disposed under the dressing body to recycle the collected chips.

[0007] However, there is a problem in that the chips tend to be released by the relative swing or rotation of the dressing body and the electrode tips during grinding work, and all the chips cannot be collected into the collection vessel, resulting in a low collection rate.

[0008] Furthermore, when air is blown to the dressing body to prevent clogging of the dressing body, the chips are released by the blown air, so that the collection rate of the chips is further decreased.

[0009] Generally, copper is often used as an electrode tip for spot welding and the like. In order to maintain a proper welding quality, the frequency of grinding is increased to increase the amount of ground chips of the electrode tip, so that, in order to reduce material cost, it is necessary to increase the collection rate of the chips and effectively recycle them.

[0010] For this purpose, various techniques are proposed in which a chip collecting apparatus is mounted on the dresser main body having a dressing body for collecting chips generated during dressing the electrode tips.

[0011] For example, Japanese Examined Utility Model Publication No. 3-18067 discloses a technique of collecting chips generated during polishing or grinding electrode tips in such a way that a cover main body is mounted on a dresser main body, and an air inlet and an air outlet are formed between the upper and lower surfaces of the cover main body and the dresser main body. Compressed air after driving a dressing body held by a holder is guided through the air inlet to the holder, and then the compressed air is guided through the air outlet to a chip collection vessel connected to the end of the cover main body.

[0012] Since the chip collecting apparatus disclosed in this prior art collects the chips using compressed air, it is necessary to provide an air inlet and an air outlet for guiding the compressed air to the periphery of the dressing body, posing a problem of complicating the structure.

[0013] Also, since compressed air after driving the dressing body is used, it cannot be assembled to a tip dresser that does not use the compressed air as a driving source, thus providing poor operability.

SUMMARY OF THE INVENTION

[0014] Accordingly, it is an object of the present invention to provide a chip collecting apparatus for a tip dresser capable of achieving downsizing and excellent versatility with a simple structure and also efficiently collecting generated chips.

[0015] In the chip collecting apparatus for a tip dresser according to the present invention, in a tip dresser for dressing the electrode tips in such a way that a dressing body held in a dresser main body is tightly pressed by a pair of opposed electrode tips and the dressing body and the pair of electrode tips are relatively slid, a chip pickup case covering the dressing body is secured to the dresser main body; tip insertion ports are opened at positions of the chip pickup case, into which the pair of electrode tips are inserted; a shielding member is disposed at the each tip insertion port for allowing the insertion of the electrode tip by elastic deformation; and a chip discharge port is provided under the chip pickup case.

[0016] In such a configuration, because of a simple structure in which the dresser main body is equipped with the chip pickup case covering the dressing body, the chip pickup case has the tip insertion ports opened therein for receiving the electrode tips, and the tip insertion ports have the shielding members for allowing the insertion of the electrode tips by elastic deformation, and the chip pickup case has the chip discharge port thereunder, downsizing and excellent versatility can be achieved.

[0017] The above and other objects, features and advantages of the invention will become more clearly understood from the following description referring to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is a perspective view of a chip collecting apparatus according to a first embodiment of the present invention;

[0019]FIG. 2 is a sectional plan view of an essential part of the apparatus of FIG. 1;

[0020]FIG. 3 is a perspective view of a chip collecting apparatus according to a second embodiment of the invention;

[0021]FIG. 4 is a sectional plan view of an essential part of the apparatus of FIG. 3;

[0022]FIG. 5 is a perspective view of a chip collecting apparatus according to a third embodiment of the invention;

[0023]FIG. 6 is a sectional plan view of an essential part of the apparatus of FIG. 5;

[0024]FIG. 7 is an exploded perspective view of a chip collecting apparatus according to a fourth embodiment of the invention;

[0025]FIG. 8 is a vertical sectional side view of the apparatus of FIG. 7; and

[0026]FIG. 9 is an exploded perspective view of a chip pickup case according to a fifth embodiment of the invention;

[0027]FIG. 10A is an upper sectional plan view of the chip pickup case shown in FIG. 9;

[0028]FIG. 10B is an upper sectional plan view of the apparatus of FIG. 10A, in a different state;

[0029]FIG. 11 and the following are according to a sixth embodiment, wherein FIG. 11 is a perspective view of a chip collecting apparatus in which a lid is in a standby state;

[0030]FIG. 12 is a perspective view of the chip collecting apparatus in which the lid is closing an arm admission port of a chip pickup case;

[0031]FIG. 13 is a perspective view of the chip collecting apparatus in which the lid closes the arm admission port of the chip pickup case;

[0032]FIG. 14 is a vertical sectional side view of the chip collecting apparatus in which the lid is in a standby state;

[0033]FIG. 15 is a vertical sectional side view of the chip collecting apparatus in which the lid is closing the arm admission port of the chip pickup case;

[0034]FIG. 16 is a vertical sectional side view of the chip collecting apparatus in which the lid closes the arm admission port of the chip pickup case;

[0035]FIG. 17 is a sectional view taken along line XVII-XVII of FIG. 14;

[0036]FIG. 18 is a sectional view taken along line XVIII-XVIII of FIG. 15; and

[0037]FIG. 19 is a sectional view taken along line XIX-XIX of FIG. 16.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Referring to FIG. 2, a welding gun 1 connected to a welding robot is provided with first and second gun arms 2 and 3, to the ends of which electrode tips 4 and 5 are removably attached to face each other. The electrode tips 4 and 5 are coaxially disposed and are relatively brought into close proximity to and apart from each other by advancing/retracting motions of at least one of the gun arms 2 and 3.

[0039] Furthermore, referring to FIG. 1, a tip dresser 6 for dressing the ends of the electrode tips 4 and 5 is disposed at a position not to interfere with welding work in a range of operation of the welding robot. A dresser main body 6 a extends laterally from the tip dresser 6. The dresser main body 6 a has a holder section 6 b at the end thereof for holding a dressing body 7 such that it can be freely rotated or swung. The dresser main body 6 a is shaped like a rectangular plane and is secured in such a manner that parallel table surfaces 6 c and 6 d are arranged substantially vertically, so called, sideways.

[0040] Accordingly, as shown in FIG. 2, the dressing body 7 is held by the holder section 6 b in a state in which concave cutters 7 a and 7 b provided at both sides of the dressing body 7 and capable of dressing the ends of the electrode tips 4 and 5 into a desired shape by polishing or grinding are substantially horizontally oriented.

[0041] Also, a motor 8 is secured to the base of the dresser main body 6 a for driving the dressing body 7 to rotate or swing. The motor 8 is not limited to an air motor using compressed air as a driving source, but may be a common electric motor.

[0042] A chip collecting apparatus 11 includes a chip pickup case 121 attached to the end of the dresser main body 6 a for covering the periphery of the holder section 6 b, and a chip collection vessel 13 for collecting chips dropped from the chip pickup case 121.

[0043] Chip inserting surfaces 12 a and 12 b of the chip pickup case 121, which face the table surfaces 6 c and 6 d of the dresser main body 6 a, are formed in a wedge shape extending from the end of the dresser main body 6 a towards the base, and tip insertion ports 12 c are opened in both the chip inserting surfaces 12 a and 12 b.

[0044] Furthermore, an end surface 12 d in the converging direction of the chip inserting surfaces 12 a and 12 b of the chip pickup case 121 is fastened to the end surface of the dresser main body 6 a with fastening screws or the like. An escape hole 12 e, into which the dresser main body 6 a inserted, is opened in the back of the chip pickup case 121. Also, a chip guide surface 12 f is formed in a taper shape converging downwards under the chip pickup case 121, and a chip discharge port 12 g is formed at the lower end of the chip guide surface 12 f.

[0045] Each of the tip insertion ports 12 c has a shielding member 14 disposed thereon. The shielding member 14 is composed of a pair of brushes 14 a and 14 b arranged to face each other at the upper and lower parts of the chip insertion port 12 c. The brushes 14 a and 14 b are made of an elastic material such as nylon, and each base of which is fastened to the upper and lower edges of the chip insertion port 12 c with screws via plates 15 a and 15 b.

[0046] The ends of both the brushes 14 a and 14 b are brought into contact with each other substantially at the center of the chip insertion port 12 c to shield it. Since the shielding member 14 is provided to prevent chips generating when dressing the electrode tips 4 and 5 from flying off to the exterior through the chip insertion port 12 c, air tightness is not required.

[0047] On the other hand, a chip collection vessel 13 is disposed under a chip discharge port 12 g opened at the lower end of the chip pickup case 121. The chip collection vessel 13 may be hung from the chip discharge port 12 g. When hanging from the chip pickup case 121, the chip collection vessel 13 is preferably lightweight; for example, it is possible to use the lower part of a plastic bottle, the upper part of which is cut, as a chip collection vessel 13.

[0048] Next, the operation of this embodiment with such a configuration will be discussed. When dressing the ends of the electrode tips 4 and 5 after spot welding work using a welding robot has been completed in a predetermined way, first, the pair of gun arms 2 and 3 provided for the welding gun 1 is advanced to the dresser main body 6 a from the front thereof (in the direction of arrow in FIG. 1) in a state in which the opposed electrode tips 4 and 5 are horizontally held, in accordance with preset teaching.

[0049] Since the tip inserting planes 12 a and 12 b formed on both sides of the chip pickup case 121 are formed in a wedge shape expanding from the front end to the rear end with respect to the advancing direction of the pair of gun arms 2 and 3, the electrode tips 4 and 5 mounted at the ends of the gun arms 2 and 3 can be guided smoothly to the tip insertion ports 12 c opened in the tip inserting surfaces 12 a and 12 b without expanding the space between the electrode tips 4 and 5.

[0050] Then, the electrode tips 4 and 5 are advanced from the tip insertion ports 12 c into the chip pickup case 121. Each tip insertion port 12 c is shielded by the brushes 14 a and 14 b extending from above and below, and when into which the electrode tips 4 and 5 attached to the ends of gun arms 2 and 3 are inserted, the brushes 14 a and 14 b are elastically deformed along the bases of the electrode tips 4 and 5 and the ends of the gun arms 2 and 3 holding the bases, and close the peripheries of the bases of the electrode tips 4 and 5 and the ends of the gun arms 2 and 3 holding the bases.

[0051] When the central axes of the electrode tips 4 and 5 face the central axis of the dressing body 7 held by the holder section 6 b, the electrode tips 4 and 5 are relatively moved to be close to each other and to bring them into contact with the cutters 7 a and 7 b provided on both sides of the dressing body 7, thereby tightly pressing the dressing body 7.

[0052] The dressing body 7 is driven to rotate or swing by the motor 8 such as an air motor provided for the dresser main body 6 a and dresses the ends of the electrode tips 4 and 5 in a predetermined way by polishing or grinding them with the cutters 7 a and 7 b provided for the dressing body 7.

[0053] In this case, since the dresser main body 6 a is supported in a state in which the table surfaces 6 c and 6 d are in upright positions, chips generated when dressing the electrode tips 4 and 5 are dropped downwards through a gap formed between the table surfaces 6 c and 6 d and the inner peripheral surface of the chip pickup case 121. Thus dropped chips are converged along the chip guide surface 12 f formed under the chip pickup case 121 and are collected through the chip discharge port 12 g into the chip collection vessel 13 disposed under the chip discharge port 12 g.

[0054] On the other hand, when dressing of the electrode tips 4 and 5 is completed in a predetermined way, the first and second gun arms 2 and 3 are separated from the dresser main body 6 a by a reverse operation from that when inserting with the welding robot, and are brought into a standby state for the next spot welding.

[0055] When the chips collected in the chip collection vessel 13 reach a predetermined amount, or periodically, the chips collected in the chip collection vessel 13 are recycled.

[0056] According to this embodiment, as described above, since the table surfaces 6 c and 6 d are in upright positions and the periphery of the holder section 6 b for holding the dressing body 7 is covered by the chip pickup case 121, chips generated when dressing the electrode tips 4 and 5 can be dropped downwards from the table surfaces 6 c and 6 d sides of the dresser main body 6 a and collected, the structure of the chip collecting apparatus 11 is simplified and a more lightweight and compact apparatus can be provided.

[0057] Also, since the tip inserting surfaces 12 a and 12 b of the chip pickup case 121 are formed in a wedge shape expanding from the front end to the rear end with respect to the advancing direction of the welding gun 1, the electrode tips 4 and 5 can be guided smoothly into the tip insertion ports 12 c without unnecessarily increasing the space between the electrode tips 4 and 5 held by the gun arms 2 and 3; therefore, workability is improved. Accordingly, even an X-type welding gun, which cannot much increase the space between the pair of electrode tips 4 and 5, can guide the electrode tips 4 and 5 smoothly into the tip insertion ports 12 c.

[0058]FIGS. 3 and 4 show a second embodiment of the invention.

[0059] In the aforesaid first embodiment, a case in which the welding gun 1 is advanced to the dresser main body 6 a in a state in which the opposite electrode tips 4 and 5 are advanced from the front of the dresser main body 6 a in a horizontal position; however, in this embodiment, a case of moving down the opposite electrode tips 4 and 5 from above of the dresser main body 6 a in a horizontal position will be discussed.

[0060] The tip inserting surfaces 12 a and 12 b of the chip pickup case 122 are formed in a wedge shape expanding from the upper surface of the dresser main body 6 a (front end with respect to the advancing direction of the welding gun 1) downwards (towards the rear end with respect to the advancing direction of the welding gun 1), and an upper end surface 12 h of the tip inserting surfaces 12 a and 12 b is secured to the dresser main body 6 a with a clamping screw or the like.

[0061] Furthermore, the pair of brushes 14 a and 14 b constituting the shielding member 14 is arranged in front and rear to face each other in the tip insertion ports 12 c opened in the tip inserting surfaces 12 a and 12 b, and is fixed with the plates 15 a and 15 b.

[0062] With such a configuration, since the tip inserting surfaces 12 a and 12 b provided at the chip pickup case 122 are formed in a wedge shape expanding from the front end to the rear end with respect to the advancing direction of the pair of gun arms 2 and 3 (the direction of the arrow in FIG. 3), the electrode tips 4 and 5 attached to the ends of the gun arms 2 and 3 can be guided smoothly into the tip insertion ports 12 c without unnecessarily increasing the space between the electrode tips 4 and 5. Since operational effects other than that are similar to those of the first embodiment, a description thereof will be omitted.

[0063]FIGS. 5 and 6 show a third embodiment of the invention.

[0064] A chip pickup case 123 according to this embodiment is shaped like a rectangle, has a chip discharge port 12 j opened in the bottom thereof, and the escape hole 12 e into which the dresser main body 6 a is inserted, at the back thereof. And the end of the dresser main body 6 a is secured to the inner surface of the chip pickup case 123 with bolts and so on.

[0065] The tip inserting surfaces 12 a and 12 b face the table surfaces 6 c and 6 d, in which the cutters 7 a and 7 b provided for the dressing body 7 held by the holder section 6 b of the dresser main body 6 a are exposed. The tip inserting surfaces 12 a and 12 b have the tip insertion ports 12 c corresponding to the cutters 7 a and 7 b, and each tip insertion port 12 c is sheathed with an elastic shielding member 21 shaped like a cap and made of rubber or the like, the outside periphery of which is fastened with a ring-shaped clip 22.

[0066] As described above, since this embodiment has a simple shape in which the chip pickup case 123 is formed in a rectangle shape and the chip discharge port 12 j and the escape hole 12 e are formed in the bottom and the back, respectively, and the tip insertion ports 12 c are formed in the tip inserting surfaces 12 a and 12 b, it is easy to manufacture; moreover, since it has a simple structure in which the cap-shaped shielding member 21 is attached to each tip insertion port 12 c, a more lightweight and compact apparatus can be provided as compared with the above embodiments.

[0067]FIGS. 7 and 8 show a fourth embodiment of the invention.

[0068] In a chip collecting apparatus according to this embodiment, even if the gun arms 2 are relatively long, the ends of the electrode tips 4 and 5 can be polished or grinded without taking up a wide space.

[0069] More specifically, the dresser main body 6 a according to this embodiment is extended in an obliquely inclined position. On the other hand, a chip pickup case 25 covering the periphery of the holder section 6 b provided for the dresser main body 6 a is formed in a longitudinal cylinder shape and the upper part thereof is oriented obliquely backwards along the inclination of the dresser main body 6 a, and the upper surface thereof faces in substantially parallel to the upper table surface 6 d of the dresser main body 6 a, from which a circular tip insertion port 25 b is arranged to project. Also, a tip insertion port 25 a is opened in the outside surface of the tip pickup case 25.

[0070] The dresser main body 6 a is inserted through the escape hole 12 e formed in one side surface of the chip pickup case 25, the end of which is fastened to the other side surface of the tip pickup case 25 with screws. Also, the cap-shaped elastic shielding member 21 made of rubber or the like is attached to the circular tip insertion port 25 b, and is locked with a ring-shaped clip (not shown). Also, a pair of brushes 26 a and 26 b constituting a shielding member 26 is disposed at the tip insertion port 25 a opened in the outside surface such that they face laterally, the bases of which are secured to the outside rim of the insertion port 25 a with plates 27 a and 27 b.

[0071] Furthermore, a chip discharge port 25 c is opened in the bottom of the chip pickup case 25, and the chip collection vessel 13 is disposed in the chip-discharging direction of the chip discharge port 25 c.

[0072] With such a configuration, even when the first gun arm 2 is relatively long, the first gun arm 2 can be arranged to face the lower table surface 6 c of the dresser main body 6 a from obliquely below, the electrode tips 4 and 5 attached to the ends can be polished or grinded without taking up a wide space. Of course, the chip collecting apparatus according to this embodiment can be applied to a case in which the first gun arm 2 is short.

[0073]FIGS. 9, 10A, and 10B show a fifth embodiment of the invention.

[0074] In this embodiment, an escape hole 30 e, in which the dresser main body 6 a is inserted, is formed in a chip pickup case 30 in the following process.

[0075] More specifically, the chip pickup case 30 is formed in a longitudinal cylinder shape, in which the welding gun 1 (refer to FIG. 2) advances into the chip pickup case 30 in a position to hold the pair of opposite gun arms 2 and 3 having the electrode tips 4 and 5, respectively, in a vertical position.

[0076] The chip pickup case 30 has a longitudinal chip insertion port 30 a for allowing the advance of the electrode tip 4 held at the end of the first gun arm 2, opened in one side surface thereof, and a circular tip insertion port 30 b for receiving the electrode tip 5 attached to the end of the second gun arm 3, projecting from the top thereof, and also a chip discharge port 30 c opened in the bottom.

[0077] The inner periphery and the outer periphery of the upper part of the chip pickup case 30 are formed in coaxial circle shape, as shown in FIGS. 10A and 10B. The tip insertion port 30 a is formed planar, in which the pair of brushes 14 a and 14 b constituting the shielding member 14 are disposed to laterally face each other and held and fixed by the plates 15 a and 15 b. Furthermore, an elastic shielding member 21 made of rubber or the like and formed in a cap shape is attached to the tip insertion port 30 b formed at the top and is locked with a ring-shaped clip 22.

[0078] The end surface of the dresser main body 6 a is brought into contact with the upper inner peripheral surface of the chip pickup case 30 via an inner spacer 31 having a convex contact surface 31 a having the substantially same curvature as the upper inner periphery of the chip pickup case 30. On the other hand, an external spacer 32 is attached on the outer peripheral surface. The external spacer 32 has a concave contact surface 32 a with the substantially same curvature as that of the outer periphery brought into contact therewith, and the chip pickup case 30 is secured to the end of the dresser main body 6 a via the spacers 31 and 32.

[0079] The positional relationship between the welding robot and the chip dresser differs from one station to another; accordingly, the advancing direction of the welding gun 1 to the dresser main body 6 a also differs depending on the station.

[0080] According to this embodiment, the escape hole 30 e and screw insertion holes 30 f are not formed in the chip pickup case 30 during assembly, and when a specific dresser main body 6 a to be mounted is determined, the dresser main body 6 a and the advancing direction of the welding gun 1 to the dresser main body 6 a are checked and then the escape hole 30 e and the screw insertion holes 30 f are worked such that the tip insertion port 30 a is formed in the optimum orientation to the advancing direction of the welding gun 1.

[0081] More specifically, for example, when the welding gun 1 advances from the front of the dresser main body 6 a, as shown in FIG. 10A, the tip insertion port 30 a opened in the side of the chip pickup case 30 is oriented to the front of the dresser main body 6 a, at the upper back of which the escape hole 30 e is formed, and the screw insertion hole 30 f is formed in front of the escape hole 30 e.

[0082] Then, the end surface of the dresser main body 6 a is inserted through the escape hole 30 e and is brought into contact with the inner peripheral surface of the chip pickup case 30 via the inner spacer 31. With the outer peripheral surface, the external spacer 32 is brought into contact, and the chip pickup case 30 is secured to the front end of the dresser main body 6 a via the spacers 31 and 32 with screws.

[0083] When the welding gun 1 advances from the side of the dresser main body 6 a, as shown in FIG. 10B, the tip insertion port 30 a is oriented to the advancing direction of the welding gun 1, the escape hole 30 e is formed at a position where the dresser main body 6 a is inserted at that time, and the screw insertion hole 30 f is formed in front of the escape hole 30 e. Then, the chip pickup case 30 is fastened to the front end of the dresser main body 6 a in a similar procedure to the above.

[0084] In this case, since the contact surfaces 31 a and 32 b of the inner spacer 31 and the external spacer 32 are formed at the substantially same curvature as that of the upper inner peripheral surface and the upper outer peripheral surface of the chip pickup case 30, the chip pickup case 30 can be attached to the end of the dresser main body 6 a in any directions. Also, because of a simple structure, it can be manufactured at very low cost.

[0085] FIGS. 11 to 19 show a sixth embodiment of the invention.

[0086] Referring to FIGS. 17 to 19, a welding gun 1 connected to a welding robot is equipped with first and second gun arms 2 and 3, to the ends of which the electrode tips 4 and 5 are removably attached to face each other. Both the electrode tips 4 and 5 are coaxially arranged and are relatively brought close to and apart from each other by advancing/retracting motions of at least one of the gun arms 2 and 3.

[0087] Furthermore, the tip dresser 6 for dressing the ends of the electrode tips 4 and 5 is disposed at a position not to interfere with welding work in a range of operation of the welding robot. The dresser main body 6 a extends from the tip dresser 6 laterally. The dresser main body 6 a has the holder section 6 b at the end thereof for holding the dressing body 7 such that it can freely rotate and swing. The dresser main body 6 a is formed like a rectangular plane and is secured such that the parallel table surfaces 6 c and 6 d are arranged in substantially upright positions, so called, sideways.

[0088] Accordingly, the dressing body 7 is held by the holder section 6 b in a state in which the concave cutters 7 a and 7 b provided at both sides of the dressing body 7 are substantially horizontally oriented. Also, the motor 8 is secured to the base of the dresser main body 6 a, by which the dressing body 7 is driven to rotate or swing.

[0089] Also, a chip collecting apparatus denoted by reference numeral 51 includes a chip pickup case 52 attached to the end of the dresser main body 6 a for covering the periphery of the holder section 6 b, and a lid 53 for opening and closing an arm admission port 52 a of the chip pickup case 52. A fixing plate 54 coming in contact with one table surface 6 d of the dresser main body 6 a is fixed to the back of the chip pickup case 52, and the fixing plate 54 and a holding plate 55 coming in contact with the other table surface 6 c sandwich the dresser main body 6 a with bolts 56, thereby fixing the chip pickup case 52 to the dresser main body 6 a.

[0090] The chip pickup case 52 is closed at the top and the back, and is opened at the front and the bottom, in which the front surface works as an arm admission port 52 a and the bottom works as a chip discharge port 52 b. Also, the chip pickup case 52 has first guide slits 57 as guide sections such that they face each other at both sides. One end of each first guide slit 57 is arranged at a position corresponding to the holder section 6 b of the dresser main body 6 a; the other end extends forwards and horizontally and is opened to the arm admission port 52 a; and steps 57 a are formed at the upper and lower sides.

[0091] On the other hand, the lid 53 is shaped like a box in which the top and the rear are opened, the both sides 53 a extend upwards, and each side 53 a has a boss 58 projecting from the substantial center thereof, as an engaging portion fitted in each first guide slit 57. Furthermore, a second guide slit 59 is horizontally formed from each boss 58 forwards, the end of which is opened to the front end of the lid 53. Also, the lid 53 has a flange 60 formed on the same plane as the lower edge of the second guide slit 59, projecting from the front part thereof.

[0092] The front half of the first guide slit 57 from the step 57 a, and the second guide slit 59 are formed to have a slit width into which the gun arms 2 and 3 of the welding gun 1 can be fitted. The boss 58 is shaped like a semicircle, and when the end of the boss 58 is brought into engagement with the step 57 a, as shown in FIG. 14, the first guide slit 57 and the second guide slit 59 are set to overlap each other in the same direction on the admission passages of the gun arms 2 and 3, viewed from the side.

[0093] At that time, the lid 53 is arranged such that a front side 53 b thereof projects slightly before the arm admission port 52 a opened in the chip pickup case 52, and the bottom 53 c is arranged on the chip discharge port 52 b side.

[0094] The lid 53 has cam pins 62 projecting from both sides thereof, which are fitted in cam holes 63 formed in both sides of the chip pickup case 52. When the end of each boss 58 is engaged with the step 57 a, as shown in FIG. 14, the cam pin 62 is engaged with the lower end of the cam hole 63. Accordingly, when the boss 58 is brought into engagement with the end of the step 57 a and also the cam pin 62 is brought into engagement with the lower end of the cam hole 63, a standby state, shown in FIGS. 11, 14, and 17, is maintained.

[0095] Also, when the gun arms 2 and 3 advance horizontally into the second guide slits 59 formed in the lid 53 to press the inner peripheries of the bosses 58, the cam pins 62 projecting from the lid 53 are guided upwards by the cam holes 63. Consequently, the lid 53 is guided to retract by the first guide slits 57, which receive the bosses 58 projecting from the lid 53, and is also guided by the cam holes 63 receiving the cam pins 62, thereby rotating clockwise, in FIG. 14.

[0096] Then, the electrode tips 4 and 5 mounted at the ends of the gun arms 2 and 3, respectively, are arranged to coaxially face the dressing body 7 held by the holder section 6 b provided for the dresser main body 6 a, at a position in which the cam pins 62 are engaged with the upper end of the cam holes 63 and also the bosses 58 are engaged with the rear ends of the guide slits 57 (a position shown in FIG. 16).

[0097] In addition, the chip discharge port 52 b formed in the chip pickup case 52 has a chip collection vessel 65 disposed below.

[0098] Subsequently, the operation of the chip collecting apparatus with such a configuration will be discussed. When dressing the ends of the electrode tips 4 and 5 after spot welding work using a welding robot has been completed in a predetermined way, first, the pair of gun arms 2 and 3 provided at the welding gun 1 is advanced to the dresser main body 6 a from the front thereof (in the direction of arrow in FIG. 14) in a state in which the opposite electrode tips 4 and 5 are horizontally held, in accordance with preset teaching.

[0099] In the lid 53, which can freely open and close the arm admission port 52 a opened in the front of the chip pickup case 52 mounted to the dresser main body 6 a, the semicircular bosses 58 projecting from the both sides 53 a thereof are engaged with the steps 57 a formed at the first guide slits 57 formed in the chip pickup case 52, and also the cam pins 62 are engaged with the lower ends of the cam holes 63, as shown in FIGS. 11, 14, and 17; thus counterclockwise rotation, shown in FIG. 14, is limited. In such a state, the second guide slits 59 formed in the lid 53 and the first guide slits 57 formed in the chip pickup case 52 overlap on the admission passages of the gun arms 2 and 3 seen from the side, and accordingly, the ends of the guide slits 57 and 59 are opened to the arm admission port 52 a side.

[0100] Subsequently, when the gun arms 2 and 3 advance to the second guide slits 59 formed in the lid 53, as shown by alternate long and short dashed lines in FIG. 14, and are then brought into contact with the inner peripheries of the bosses 58 formed at depths of the second guide slits 59, as shown by a solid line, the bosses 58 retract along the first guide slits 57. At that time, since the cam pins 62 projecting from the both sides 53 a of the lid 53 are guided upwards by the cam holes 63 formed in the sides of the chip pickup case 52, the lid 53 is moved horizontally and rotated clockwise (a state shown in FIGS. 12, 15, and 18).

[0101] When the central axes of the gun arms 2 and 3 are brought onto the central axis of the dressing body 7 held by the holder section 6 b of the dresser main body 6 a, the cam pins 62 are brought into engagement with the upper ends of the cam holes 63, and the bosses 58 are brought into engagement with the depths of the first guide slits 57, thereby stopping the horizontal movement and the clockwise rotation of the lid 53.

[0102] Then, the arm admission port 52 a of the chip pickup case 52 is closed by the bottom 53 c, the front side 53 b, and the flange 60 provided for the lid 53, as shown in FIGS. 13, 16, and 19. Furthermore, since the second guide slits 59 are rotated obliquely upwards with respect to the first guide slits 57, the peripheries of the bosses 58 supporting the gun arms 2 and 3 are also closed to a certain extent. Also, since the bottom 53 c of the lid 53 is rotated toward the arm admission port 52 a of the chip pickup case 52, the chip discharge port 52 b of the chip pickup case 52 is opened.

[0103] Subsequently, the electrode tips 4 and 5 mounted at the ends of the gun arms 2 and 3 are relatively moved in the direction to come close to each other, and are brought into contact with the cutters 7 a and 7 b each provided on both sides of the dressing body 7, thereby tightly pressing the dressing body 7.

[0104] The dressing body 7 is driven to rotate or swing by the motor 8 such as an air motor provided for the dresser main body 6 a, and dresses the ends of the electrode tips 4 and 5 in a predetermined way by polishing or grinding them with the cutters 7 a and 7 b provided for the dressing body 7.

[0105] In this case, since the dresser main body 6 a is supported in a state in which the table surfaces 6 c and 6 d are at upright positions, chips generated when dressing the electrode tips 4 and 5 are dropped downwards through a gap formed between the table surfaces 6 c and 6 d and the inner peripheral surface of the chip pickup case 52; the chips thus dropped are collected through the chip discharge port 52 b into the chip collection vessel 65 disposed thereunder.

[0106] On the other hand, when dressing of the electrode tips 4 and 5 is completed in a predetermined way, the first and second gun arms 2 and 3 are separated from the dresser main body 6 a with the welding robot by a reverse operation from that when inserting, and are brought into a standby state for the next spot welding.

[0107] When the gun arms 2 and 3 retract, they press the lower ends of the second guide slits 59, and then, the lid 53 is going to rotate counterclockwise. Then, the cam pins 62 projecting from the sides 53 a of the lid 53 are guided downwards by the cam holes 63 formed in the sides of the chip pickup case 52, and the bosses 58 are moved forwards along the first guide slits 57. Accordingly, the lid 53 is rotated counterclockwise and is also moved horizontally toward the arm admission port 52 a.

[0108] Then, the arm admission port 52 a is gradually opened, and subsequently, the end of each boss 58 is brought into engagement with the step 57 a formed at each first guide slit 57, and also, each cam pin 62 is brought into engagement with the lower end of each cam hole 63, thereby stopping the counterclockwise rotation and the forward and horizontal movement of the lid 53 to return to a standby state.

[0109] Consequently, the lid 53 opens the arm admission port 52 a, and the second guide slits 59 for receiving the gun arms 2 and 3 and the first guide slits 57 formed in the chip pickup case 52 overlap on the admission passages of the gun arms 2 and 3, seen from the side, thereby separating the gun arms 2 and 3 from the chip pickup case 52.

[0110] According to this embodiment, as described above, since the arm admission port 52 a opened in the chip pickup case 52 is opened and closed by the lid 53 interlocking with the advancing motions of the gun arms 2 and 3, power for opening and closing the lid 53 becomes unnecessary, the structure is simplified, thus achieving low-cost manufacturing and downsizing.

[0111] Also, since the chip pickup case 52 prevents chips generated when dressing the electrode tips 4 and 5 to be released to the periphery and drops most of the chips into the chip collection vessel 65, the chips generated during dressing can efficiently be collected.

[0112] The present invention is not limited to the above embodiments, and it is also possible to fix a weight in the vicinity of the inner surface between the front side 53 b and the bottom 53 c of the lid 53 in order to stably hold the lid 53 in a standby state, shown in FIG. 14.

[0113] Having described the preferred embodiments of the invention referring to the accompanying drawings, it should be understood that the present invention is not limited to those precise embodiments and various changes and modifications thereof could be made by one skilled in the art without departing from the spirit or scope of the invention as defined in the appended claims.

[0114] According to the present invention, as described above, the collection rate of chips generated during dressing electrode tips can be increased and the rate of recycle can be improved.

[0115] Also, the structure of the chip pickup case is simple, thereby achieving downsizing and high versatility. 

What is claimed is:
 1. A chip collecting apparatus for a tip dresser, comprising: a tip dresser for dressing a pair of opposite electrode tips by tightly pressing a dressing body held in a dresser main body with the pair of electrode tips and relatively sliding the dressing body and the pair of electrode tips; a chip pickup case secured to the dresser main body for covering the dressing body; tip insertion ports opened at positions of the chip pickup case, into which the pair of electrode tips is inserted; a shielding member disposed at the each tip insertion port for allowing the insertion of the electrode tips by elastic deformation; and a chip discharge port provided under the chip pickup case.
 2. The chip collecting apparatus for the tip dresser, according to claim 1, wherein: the dresser main body is supported in a state in which the dressing body is oriented in a substantially horizontal direction, and surfaces of the chip pickup case, in which the tip insertion ports are opened, are formed in a wedge shape expanding from the front end to the rear end with respect to the advancing direction of the pair of electrode tips.
 3. The chip collecting apparatus for the tip dresser, according to claim 2, wherein: the advancing direction of the pair of electrode tips is horizontal, and both the surfaces of the chip pickup case, in which the tip insertion ports are opened, are formed in a wedge shape expanding from the front to the rear with respect to the advancing direction of the electrode tips.
 4. The chip collecting apparatus for the tip dresser, according to claim 2, wherein: the advancing direction of the pair of electrode tips is upward, and both the surfaces of the chip pickup case, in which the tip insertion ports are opened, are formed in a wedge shape expanding from above downwards.
 5. The chip collecting apparatus for the tip dresser, according to claim 1, wherein: the surfaces of the chip pickup case which face the dressing body are brought into close vicinity of the dressing body, the tip insertion ports are opened in the facing surfaces, and an insertion port for the dresser main body is opened at the rear of the chip pickup case.
 6. The chip collecting apparatus for the tip dresser, according to claim 1, wherein: the dresser main body is supported in a state in which the dressing body is oriented obliquely vertically, the upper part of the chip pickup case is bent along the inclination of the dresser main body, and the tip insertion ports are opened in the upper surface of the chip pickup case which faces the dressing body and the outer side of the chip pickup case.
 7. The chip collecting apparatus for the tip dresser, according to claim 1, wherein: at least the upper inside periphery of the chip pickup case is shaped like a cylinder, and a contact surface having the substantially same curvature as that of the upper inside periphery of the chip pickup case is provided at the end surface of the dresser main body inserted in the upper inside periphery of the chip pickup case from the side.
 8. A chip collecting apparatus for a tip dresser, comprising: a tip dresser for dressing a pair of opposite electrode tips by tightly pressing a dressing body held in a dresser main body with the pair of electrode tips and relatively sliding the dressing body and the pair of electrode tips; a chip pickup case secured to the dresser main body for covering the dressing body; an arm admission port opened in the chip pickup case in the advancing direction of gun arms having the electrode tips at the ends thereof; and a lid provided at the arm admission port and opened and closed by advancing/retracting motions of the gun arms.
 9. The chip collecting apparatus for the tip dresser, according to claim 8, wherein: the lid includes an engagement section engaging with the gun arms at the rotation center thereof; the chip pickup case includes a guide section for supporting the engagement section formed at the lid, formed along the advancing direction of the gun arms; and one of the lid and the chip pickup case includes a cam for rotationally moving the lid and the other includes a cam pin engaging with the cam.
 10. The chip collecting apparatus for the tip dresser, according to claim 8, wherein: the dresser main body is supported in a state in which the dressing body is oriented in a substantially horizontal direction, and a chip discharge port is opened in the bottom of the chip pickup case.
 11. The chip collecting apparatus for the tip dresser, according to claim 9, wherein: the dresser main body is supported in a state in which the dressing body is directed in a substantially horizontal direction, and a chip discharge port is opened in the bottom of the chip pickup case. 